Conduit tractor



Oct. 16, 1934. u. GUTHRIE CONDUIT TRACTOR Filed March 24, 1932 5 Sheets-Sheet INVENTOR. .Tarifes azfv @ff/Jaa v Dag A TTORNEY.

Oct. 16, 1934. J. GUTHRIE CONDUIT TRACTOR 3 SheetsSheet 2 Filed March 24, 1952 INVENTOR. James z/f/fr'ie Muf ATTORNEY Oct. 16, 1934. v 1. GTHRlE I 1,976,990

CONDUIT TRACTOR Filed March 24, 1932 Y lSheets-Sheet 3 /5 /4 O O O 0.0 o /0" 30 l n @mi z t* z8 l I '-il@ o Q (D 1 i?- \QA "Y: a 4239,' o mr 4.

mi /4. u' n l l O O o 30 o o o o ol 0 /0' 3/ INVENTOR.

@man z/rz ATTORNE 5- .me cables` and the like.

Patented Oct. 16, 1934 .ooNDUI'r TRACTOR James Guthrie,` Elyria, Ohio" Application March 24, 1932,` serial No. 600,947

12 claims. (olv. 17a- 377) The present invention relates to a self-propelled vehicle adapted to travel through the interior of conduits,l d-ucts,l and tubes which are intended to ser-v-e as protective housings for elec- The device embodying lthesubject matter .of the present invention is adapted to be used for cleaning the interior of -suc'h :conduits and for drawing cables and wires therethrough. y lThe general object and nature of my invention is toprovide a -s'elf-propelledendless type of tractor which shall have rm positive tractional engagement with the sides of the conduit, by virtue of the provision of the power actuated means Atending to force the intermediate run ofthe endless tracks in an outward direction. Another object is to provide means iforautomatically increasing the gripping pressure of the traction elementsproportionately to resistance to the passage of the tractor. Objects and'advantages additional lto those above enumerated shall become apparent as thea-following description proceeds. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fullydescribed and particularly pointed out in the claims. l Y

The annexed drawings and the following -description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in whichlthe principle of the invention may be used." Y

f: In saidannexed drawings: Fig. 1 is a view'of the endless track portion of 35 the device constructed according to the principle of my. invention, with one track removed in order Yto more satisfactorily illustrate the detailed construction; Fig. 2V is a view ofv the driving motor or rear portionof my device; Fig. 3 is alviewtaken lina plane normal `to that of Fig. 1; Fig.l 4 is aseotion takensubstantially upon line 4 4 of Fig. 3"; Fig.' 5 is a section taken substantially upon line 5`5 of Fig.`3; Fig. 6 is azsection taken substan-l ftially upon line 6-6 of Fig. 3; Fig. 'lis a fragmentaryv View showing the endless track raising mecl'xanisnri in full operating position; Fig. V8 is a section taken substantially uponline 8-`8 of Fig. A5; Fig. 9 is a sectional-view of the pneumatic power connecting jointand-taken substantially upon line 9:-9of Fig. 2; FiglQ isa section takensubstan- .tially upon line 10"-1'0 `of Fig. `2.

.Since underground cable-conduits are generally constructed vin' a circular; square, -o'r rectangular cross-sectional Iform, it lis to belunderstood that *555 the .endless .tracht-engaging elements maybe vso gear connection is not herein shown inasmuch as disposed as vto most'suitably contact with the in# ner surface' of such conduits. For example, ina tractor adaptedfor luse with a conduit of circular cross section, the tractionalI engaging elements `may be three in number and axiallydisposed -upon 30 the apexesof an equilateralor isoscelestriangle. The deviceherein described, however, is adapted for use with a conduit having a-squarev or rectangular cross section in which case the endless tracks 'are four in number and arranged in two 65 parallel planes. e 1 e A Now referring more particularlyV to the'draw# ings, and as shown in Figs. '1 to `3 inclusive, my device consists of a longitudinal frame member 'indicated generally by the numeral l in which 70 there is the centrally disposed rotatable'sliaft'y The forward `end of the shaft 2 mounts a drilling lor reaming tool 3. The rearward end of thero'- tating central shaft 2 is connectedto an air motor lindicated generally by the numeral 4. The air motor 4 may be of any well known design and `mechanicallyconnected to the central shaft 2 through a series of reduction gears. f The precise construction ofthe air motor and the reduction '80 such mechanicalconstructions are well known in the art and Vhence need not Vbemore specifically disclosed. An'y air pressure supply coupling 5 l*is connected to the 4ileXible hose section 6 which is, in turn, connected to the Vmetal hose coupling 7.

The forward and rear ends of the frame memjber 1 are composed of the enlarged portions 8 and'9v respectively which serve as means for'supporting the endless track rotating shafts ,10"and 10'. One or more of the shafts 10 are mechanically connected through a worm and spiral gear construction to the Y,central driving shaft 2. The shafts 10" garejmovably mounted againsta spring load in order to maintain tension inthe endless 'chain 12. The precise details of this latter form 'of 'gearing and shaft 4mounting construction are fully disclosed and described in my co-pending applicationv Serial No. 573,509, led 'November 6., 1931. The transverse shafts 1Q carry the sprock'f ets 11v which in turn serveas means for rotatably 5100 supportingthe endless `chains 12. The endless 'chains 12l carry` a plurality ofl projectingvrubber V'pads or feet `13. 4'lifhe intermediate run ofthe end'- less chains 12 is supported by a number of flanged pulleysll mountedupon the movable shafts 15. '105 A pairof guide wheels 16 andl'l are mounted upon the `forward end of the frame 1:. These guide wheels land llare 4Supported-upon spring loaded pivoted arms which-tend tourge them in an outward direction and serve as a means tend- 'i110 the frame 1.

heads 28. Vform of construction, are diametrically disposed ing to maintain the forward end or nose of the tractor in a centrally disposed location while traveling through the conduit.

A pair of cable connecting link arms 18 and 19 are secured to the rear end of the frame 1 by means of suitable fastening bolts 20 and 21 respectively.

It will thus be seen that rotation of the central shaft 2 by virtue of the power supplied to the pneumatic motor 4 will cause rotation of the forwardly disposed drill or reaming tool 3 and simultaneously cause the endless tracks 12 'which are in engagement with the side walls of the conduit,v to rotate about the end supporting shafts 10,

whereby the entire tractor unit will be given a forward motion. An electric cable lor cleaning tool may be connected to the rods 18 or 19 and thereby forcibly drawn through the interior of the conduit. v.

In order to force the intermediate run of the endless tracks 12 into positive resilient engagement with the inner wall surfaces of the conduit, I have provided the following described mechanism. The transverse shaftsV 15 which carry the flanged supporting pulleys 14 are mounted upon the ends of the movable supporting elements 22. vThe supporting elements 22 are preferably composed of fairly stiff spring wire stock and are coiled about the xed shafts 23 mounted upon Cotter pins 24 may be provided in order to prevent axial displacement of the coiled portion of the elements 22 upon the xed shafts The opposite ends ofthe elements 22 are attachedto the longitudinally extending link arms 26. The link arms 26 are, in turn, connected by the connecting arms 27 to the cross The cross heads 28, in the present .ber are mounted in the cylinder block 35 which is positioned to .the rear of andA immediately adjacent the end of the frame member 1, as shown in Fig. 8.

Pneumatic power is supplied to the cylinders 34 through the connecting pipe 36 which, as shown `in Fig. 6, communicates with the smaller interior passages 37 leading tothe head ends. of the cylinders 34.

. Now referring to Figs. 9 and 10, it will be. seen removable casting 384secur'ed to one side thereof by means of suitable fastening bolts. The end of the air tube 36 is thus held in connecting position with the inner passage 39 communicating with the main pressure supply duct 40 in the connection 5. It will thus be seen by reference to Fig. 7, that exertion of pressure through the tube 36 and thence to the cylinders 34 will tend to force the connecting' rods 30 to a rearward position. This latter action in turnis communicated to the link arms 26, likewise forcibly urging them to a rearward position. .Inasmuch as the transverse shaft supporting-elements `22 are connected to the link arms l26, they will be rotated about their xed points of support, namely, the shafts 23, with the resultthat `the movable .transverse shafts .15 and pulleys 14will be forced in an outward direction. Therefore, introduction of pressure to the cylinders 34 will function to forcibly urge the intermediate run of the endless tracks 12 in an outward direction -against the inner walls of the conduit. It should be further noted that, inasmuch as the tube 36 is connected directly to the main power supply line, when the tractor is slowed up by reason of encountering some resisting obstruction in the conduit, there will occura Ybuilding up of back pressure in the main supply tube 40 with the result that a greater pressure will be exerted in the cylinders 34, which latter result tends to urge the intermediate track vsupporting elements into more forcible engagement with the conduit walls. Furthermore, this rlatter described action is automatic in operation,

that is whenever the tractor in its forward motion comes in contact with some obstruction or resistance toits travel, it will be accordingly slowed down and the gripping or traction pressure will be accordingly increased.4 Inaspecimen device `constructed according to the above described specifications, it has been found that a pneumatic power supply pressure of one hundred pounds per square inch will result in imparting a dead pull of three hundred and seventy pounds to the tractor itself.

It should be further noted, that although I have described the present embodiment of my invention as adapted for use with a-pneumatic power supply, nevertheless, an equivalent type of pressure supply, ,such as hydraulic pressure may equally well be used so long as the spirit of my invention is not violated. The use of' pneumatic pressure, however, is particularly to be desired inasmuch as the exhaust 4air functionsk to dilute and remove any contaminating orexplosive gases found to be present in an underground conduit, thereby eliminating the hazards of explosion and gas poisoning of workmen.

Other modes of Vapplying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means -stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

l. In a self-propelled tractor for vthe interior of conduits and the like, the combination of a frame, a, plurality of endless tracks mounted longitudinally on said frame, and means actuated by the prime moving power supplied to said tractor for urging the intermediate run of said tracks in an outward direction from said frame. A.

2. In a self-propelled tractor for the interior of conduits and the like, the combination of a frame, a plurality of endless tracks mounted longitudinally on said frame, a plurality of transm35 lconnecting arms pivotally mounted onsaid frame and having one end engaging `with said shaft, a

plurality of longitudinally, disposed link bars having the other endl of said connecting arms se;-

kso

cured thereto, and power means for moving said bars in order to move said shafts in an outward direction from said frame.

4. In a self-propelled tractor for the interior of conduits and the like, ythe combination of a frame, a plurality of endless tracks mounted longitudinally on said frame, a plurality of transverse shafts movably mounted on said frame for supporting the intermediate run of said tracks, resilient connecting arms pivotally mounted on said frame and having one end engaging with said shaft, aplurality of longitudinally disposed link bars having the other ends of said connecting arms secured thereto, and power means for moving said bars in order to move said shafts in an outward direction from said frame.

5. In a self-propelled tractor for the interior of conduits and the like, the combination of a fra-me, a plurality `of endless tracks mounted longitudinally on said frame, a iiuid pressure n'rotor for moving said tracks, a power supply conductor connected to said motor, power means for dis placing said tracks in an outward direction from said frame, and a conduit connecting said power sup-ply conductor to said track displacing means.

6. In a self-propelled tractor for the interior of conduits and the like, the combination of a frame, a plurality `of endless tracks mounted longitudinally on said frame, a iluid pressure motor for moving said tracks, a pressure power supply conductor connected to said motor, a plurality of shafts movably mounted on said frame for supporting the intermediate run of said tracks, pressure cylinders carried by said frame, pistons movable in said cylinders, yand means connecting said pistons to said movable shafts.

7. In a self-propelled tractor for the interior of conduits and the like, the combination of a frame, a plurality of endless tracks mounted longitudinally on said frame, a fluid pressure motor for moving said tracks, a pressure power supply conductor connected to said motor, a plurality of shafts movably mounted on said frame for supporting the intermediate run of said tracks, pressure cylinders carried by said frame, pistons movable in said cylinders, means connecting said pistons to said movable shafts, and a conduit connecting said cylinders to said power supply conductor.

8. In a self-propelled vehicle for the interior of conduits and the like, the combination of a frame, a plurality of endless tracks mounted longitudinally on said frame, a fluid Ipressure motor for moving said tracks, a pressure power supply conductor connected to said motor, a plurality of transverse shafts movably mounted on said frame for supporting the intermediate run of said tracks, connecting arms pivotally mounted o-n said frame and having vone end engaging with said movable shafts, a plurality of longitudinally disposed link bars having the other ends `of said connecting arms secured thereto, pressure cylinders positioned in said frame, pistons movable in said cylinders, connecting rods between said lpistons to said link bars anda con-duit connecting said cylinders to said power supply conductor.

9. In a self-propelled vehicle of the character described, the combination of a plurality of endless tracks, resilient supporting means carrying said vehicle for varying the degree of resiliency of said supporting means.

1l. In a self-propelled vehicle yof the character described, the combination of a frame, a plurality of endless tracks mounted -upon said frame, resilient supporting means for urging the intermediate run of sai-d tracks outwardly from said frame, and means actuated by the prime moving power supplied to said vehicle for varying the n the surface to be traversed, the `force exerted by fr said power means being directly proportional to the force necessary to actuate said track.

JAMES GUTI-IRIE. 

